Sign in

When Cicadas Fall in Love

It is the nature of youth to make a racket. This happens reliably in New York City every weekday between two and three in the afternoon, when school lets out. Teen-agers spill onto the sidewalks and descend below ground into the subway, where, having loosened their uniforms and shed decorum, they occupy the airwaves—shouting, flirting, arguing, cajoling, checking in, checking out. They sing the song of themselves, loudly, jubilantly, to a rhythm that only they can hear.

In the coming days, the woods and lawns in and around the city will experience a similar visitation, from periodical cicadas. For seventeen years, juveniles of three species of the genus Magicicada have been underground, sipping on rootlets and quietly growing. When the soil reaches the right temperature—64 degrees F, measured eight inches down—they will emerge in astonishing numbers, molt, climb into the trees, and, for the remaining three weeks or so of their lives, sing an exoskeleton-rattling chorus. Periodical cicadas are distinct from the species that emerge annually, in far lesser numbers, and sing in the dog days of summer. (There are seven Magicicada species in all, four of which emerge, every thirteen years, in the Southern and Midwestern states; they seem to like prime numbers.) The reason for the long life cycle is the subject of debate, but the point of the din is clear: to court and mate and so start the period anew.

The racket comes from the males. Each sings by rapidly clicking a portion of his abdomen in and out, as one might click and unclick an empty soda can. He alters its shape and position to make the frequency rise and fall, and because his abdomen is mostly hollow, it acts as a resonance chamber that amplifies the sound and broadcasts it for some distance. (Cicadas can relax and desensitize their auditory organs, so they don’t deafen themselves.) The quality of the song varies among species; some cicadas in Southeast Asia produce “spectacularly musical songs, with more pure tones, complex frequencies, and harmonics,” David Marshall, a cicada researcher at the University of Connecticut, in Storrs, told me. “There are some that sound like birds, whereas ours are more grating, although some make a pleasant syrupy drone. When Magicicada is out, it sounds like a U.F.O. is landing.”

New York’s seventeen-year brood, known to scientists as Brood II, extends from Connecticut to Georgia and has been emerging south of here for a couple of weeks already. Marshall was on his cell phone, in the passenger seat of a car in Elkin, North Carolina, near the southern limit of the emergence; John Cooley, a colleague, was driving. “We’re driving around with our windows open, listening,” Marshall said. The three seventeen-year species aren’t equally abundant everywhere, and the researchers are interested in, among other things, charting their respective distributions, to test ideas about cicada ecology and evolution. Over the past ten years, Marshall and his wife, Kathy Hill, have recorded most of the cicadas of eastern North America, as well as many southwestern species, and made the songs available on their Web site, insectsingers.com.

“We’re using their sounds to tell us which species are present, and getting out occasionally, making collections for DNA sequencing,” he said. Studying periodical cicadas sounded a lot like a road trip, minus the car stereo. “We’re just driving around in the car a lot, pretty much all day, from nine in the morning until the sun goes down,” Marshall said. “Then we’ll crash at a campground and have dinner. Periodical cicadas don’t last all that long when they come out; you only have a few weeks to gather all the information you can.”

Seventeen years ago, when Brood II last emerged, Marshall and Cooley were “driving around and around” Farmville, Virginia, and studying cicadas there, Marshall said. The two were then grad students at the University of Michigan and had recently cracked the code to Magicicada’s mating behavior. They knew that each emerging brood comprises more than one species, each with its own male song, and they saw a lot of cicadas paired off, always with their own species. “But nobody knew how the female was saying, ‘Yeah, I’ll mate with you,’ “ Marshall said. “We were trying to figure out how in the world the sexes were talking to each other.” This proved challenging, in part because, as Cooley and Marshall also discovered, most females mate only once.

“It was pretty frustrating,” Cooley said. “We couldn’t understand it. We’d put males and females together, they’d just sit there and look like lumps. It turns out we’d just been grabbing females that had already mated.”

Finally, Marshall and Cooley placed themselves in a large cage with a horde of male cicadas and females that had not yet mated and observed what each was doing. The male pursues what Marshall calls “a sing-fly strategy”: he lands near a promising female, hums a bar or two, and waits; if she doesn’t respond, he flies on. Marshall and Cooley discovered that the female signals her readiness by flicking her wings. The researchers hadn’t paid attention to it at first, Marshall said: “You’d see the females flick their wings all the time at males that are pestering them—get off, go away!” But timing is everything. The wing-flick is an invitation only if it comes four-tenths of a second after the male’s song ends; it’s not what she says but when that matters. The males are jumpy, “sensitive to the slightest response,” Marshall said. The wing-flick sounds like a finger snap; its hold on the male is so strong that if you snap your fingers near one, he will follow and sing to them. Marshall said, “If you keep it up and present him with a suitably sized, dark-colored object, such as a Bic pen with a black cap or a wristwatch, he will attempt to mate with it.”

Having waited seventeen years to mate, Mr. Magicicada has his work cut out for him. The available females are quickly spoken for, so the males tend to zero in on females that are just barely ready to mate, or not even—the tweens. “The males are flying around looking for these very subtle signals, these unenthusiastic little shrugs,” Marshall said. If you go looking, often you’ll find a male and female paired off “just sitting there. The male is proceeding very delicately, like he’s afraid of pushing too hard. He begins by leaning forward, vibrating a little, lifting his leg to touch her. If she budges, that’s the sign that she’s not interested—yet. Long, protracted courtships are not uncommon.”

Human males have been known to shout over one another to keep a woman’s attention; male cicadas do this, too. A courting male that sits around waiting for a female to mature has to ward off every other salesman who comes calling. If one lands and launches into his song, the first male produces an “interference buzz,” a messy version of his own song that drowns out the other male’s signal so the female never hears it, Marshall said. “It only has to work one or two times. The other male just flies off; he doesn’t even recognize what’s going on.”

I remarked to Cooley that it must be hard to learn much about an organism that appears only once every seventeen years. He reminded me that although the periodical cicadas of the East Coast are emerging this year, other regions also have their periodical broods; there’s always a crop of teen-agers coming of age somewhere. “Brood II is in the New York metropolitan area, so it gets a huge amount of press,” Cooley said. “But last year I was working on periodical cicadas, too, down in the Shenandoah Valley. Next year it’s western Illinois and Iowa, after that Oklahoma and Texas; those are thirteen-year cicadas. In 2016, it’s Brood V, in a big band from Ohio back to the Shenandoah Valley again; those are seventeen-year cicadas. Almost any year you can find periodical cicadas, you just have to pick up and go to them. I think of it as being the ultimate groupie.”

As one gets older, the presentation of youth can begin to feel apocalyptic. It is always rising up, always gaining in number—insistent, heedless, both a memory and a premonition. “Working with seventeen-year cicadas brings the past into a different kind of perspective,” Marshall told me. “The last time this brood was out was seventeen years ago; a lot has happened since then. You’re having those moments with every brood that comes up; it’s always seventeen years ago. Every year, I’m saying, basically, ‘Ah, this is the brood from ’96, we were in this particular place.’ “ It’s like when you hear a song on the radio, he said: “It takes you right back to where you were.” He added, “It certainly makes me think how old I’ll be next time. That’s always where your thoughts go when you think forward from a brood.”

When I first spoke to Cooley, he was stuck in traffic near Harrisburg, Pennsylvania, on his way to helping to move his father-in-law into an assisted-living facility. Cooley runs a Web site, magicicada.org, where visitors can note cicada sightings; the details feed into a database that helps biologists map the boundaries and makeup of different broods. He still conducts fieldwork, although it no longer occupies all of his time. “Your career doesn’t always take the turn that you expect,” he said. “It’s not a good story, but that’s the way it works. We may want to know about the lives of seventeen-year cicadas, but our own lives often intrude. I couldn’t have told you that seventeen years ago.”